Tanning.



: iiNrrnn s'raras ra ranr curios.

RENE :BoHN, oscnn BALLY, AND nuco WOLEF,

'r0 BADISCHE ANILIN & SODA FABRIK,

MANY, A coRPoRATIoN.

TANNING.

1 1,281,494. Specification of Letters latent.

I Drawing.

rials hitherto employed all possess an amor phous character.

Now we have made the discovery that we can transform hides into a'valuable leather of good properties by-treating them with an aqueous solution of sulfonated aromatic hydrocarbons containing a system of at least three condensed nuclei, which sulfonated products generally represent substances of a crystalline character. As instances of hydrocarbons of the aforesaid kind we mention anthracene, phenanthrene, fluorene and the like, or derivatives thereof, such as halogen substitutionproducts of the said hydro carbons. The said sulfonated products can be employed either alone or in the form of mixtures of several sulfonic acids of the same hydrocarbon or of difi'erent hydrocarbons and an addition can be made of other tanning materials or other suitable bodies. Besides, the tanning process can be carried out in the ordinarymanner. Suitable mixtures of sulfonated hydrocarbons can be produced bytreating, for instance, anthracene with a sulfonating agent so as to give rise to a mixture of anthracene disulfonic acids, or, by sulfonating crude'anthracene, conta ning phenanthrene, fluorene andlike hydrocarbons, so, as to produce a mixture of sulfonic acids ofthe said hydrocarbons. The sulfonic acidscan be directly employed inthe free state or their salts, in particular their alkalisalts, can be used with an addition of an acid.

For the purpose of further illustrating the invention we give the followingexamples, but the invention is not confined tothese examples.' The parts are by weight.

Example 1.

Dissolve, at. ordinary temperature, 50 parts of a mixtureof the sodium salts of anthracene, -1.5 and LS-disulfonic acids (prepared by sulfonating anthracene of about 80 per cent. purity and purifyin ,if desired, by means of the calcium salts? 0F MANN'HEIM, GERITANY, ASSIGNORS OI LUDWIGSHAFEN-ON-THE-RHINE, GER- Patented Oct. 15,1918.

Application filed December 80, 1916. Serial No. 139,872.

- 1000 parts of Water, acidify the solution by adding 50 parts of dilute sulfuric acid of 10%, introduce into this solution the hides which are deprivedof lime by a treatment with bisulfite solution and treat until the hides are thoroughly tanned. The leather is then washed and fatted in the usual way; it is of a brown color with brown cut and possesses good strength.

Ewamp lc 2.

Dissolve 40 partsof dichlor-anthracenedisulfonic acid in 1000 parts of hot water, acidify'by adding 100 parts of dilute sulfuric acid of "10% and allow to cool. Then.

introduce the hides which are deprived of lime by treatment with bisulfite solution and treat until the hides are thoroughly tanned.

The leather is finished as usual; it has a dull yellow color with a light reddish yellow cut and possesses a strong fiber condition.

In an analogous manner, hides can be tanned with solutions of other sulfonic acids of anthracene, such as anthracene-l-sulfonic acid sodium salt, anthracene-2-sulfon1c acid,

anthracene-1.5- or -1. 8- or -2.6- or -2.7-disulfonic acid sodium salts, or 1.4-dichlor-antlzhlg'acene-sulfonic acid sodium salt and the Ewample 3. l

70 parts of the mixture of the potassium salts of phenanthrene 2- and 3- sulfonic acids, such as is obtainable as described in Annalen dc'r' Uhemz'e vol.'321, p. 251 or Bem'chte der Deutsche n, Uhemischen Gesellschaft, vol. 34:,

p. 4004, are dissolved at the ordinary temperature in 1000 parts of water and added with 70 parts of sulfuric acid of 10%. Then introduce the hide treated with bisulfite solution and treat until it is thoroughly tanned. The leather is finished as usual. It is a slightly swelled leather of a brown color turning to white in the interior.

The phenanthrene-2 and 3-sulfonic acid canbe replaced by the sodium salts of the mixed sulfonic acids obtained by sulfonating crude phenanthrene of say 84 per cent. purity. A brown leather with a light brown cut is thereby obtained possessing a soft condition and good grain.

Example 4.

70 parts of the-mixture of fiuorene sulfonic acid sodium salts, obtained by 'sulfonating fluorene with sulfuric acid"oi:"66%,

are dissolved in 1000 parts'of warm. water leather is washed and fatted in the ordinary manner. It is a slightly swelled leather with soft grain and a yellowish-white color. In

an analogous manner the easily soluble disulfonic acids of fluorene (see Annalen der Ohemie vol. 390, p. 217) can be employed. They yield a soft-yellowish leather.

e claim:

1. The process of tanning hides which comprises treating hides with a bath containing a sulfonated aromatic hydrocarbon which consists of a system of at least three condensed nuclei. i

2. The process of tanning hides which comprises treating hides with a bath containing the sulfonic acids of the hydrocarbons contained in crude anthraccne.

3. The process of tanning hides which comprises treating hides. with a bath containing an-anthracene-sulfonic acid.

4:.The process of .tanning hides which comprises depriving hides of lime and then treating them with a bath containing a sulfonated aromatic hydrocarbon which consists of a system of at least three condensed nuclei.

5. The process of tanninghides which comprises depriving hides of lime and then treating them with a bath containing an anthracene sulfonic acid.

6. The process of tanning hides which comprises depriving hides of lime and swelling them and then treating them With a bath containing an anthraccne sulfonic acid.

7. The process of tanning hides which comprises treating hides with a bath containing an anthra'c'ene sulfonic acid salt and an acid.

8. As a new article of manufacture a leather containing-as a tanning constituent I a sulfonated aromatic hydrocarbon which consists of a system of at least three condensed nuclei.

'9. As a new article of manufacture a leather containing a'sa tanning constituent a sulfonated anthracene derivative.

In testimony whereof we have hereunto set our hands.

RENE BOHN. osoan RALLY. HUGO WOLFE. 

